1. Field of the Invention
The invention relates to a testing device for hazard alarm systems, particularly for their communication circuit, which is responsible for data communication and for control of a plurality of devices connected by way of a device loop.
2. The Prior Art
Since hazard alarm systems are supposed to warn the owners or operators of endangered industrial facilities or storage facilities before the occurrence of major damage due to fires, chemicals, or other hazardous substances, in as timely a manner as possible, so that suitable countermeasures can be taken, great demands are made on their reliability and operational safety.
For this reason, such systems, particularly fire alarm systems for detecting fires and extinguishing controllers for extinguishing fires, must function in reliable and problem-free manner over extended periods of time, under different requirements and operating conditions.
In order to keep the alarm and system technology that is used free of problems over many years, it must be possible to recognize all the error sources that can occur over the course of the time of operation under real ambient conditions, and particularly in rough industrial areas, at an early point in time, to report them, and to eliminate them, if at all possible.
Because of the rapid spread of hazardous situations, such as fires, toxic gases, or the like, during a short period of time, rapid and reliable detection, alarm triggering, and combating are particularly important. This particularly relates to the proper functioning of the hazard or fire alarm that stands at the tip of the signal chain.
Functional problems, not only of the connection lines used as supply lines and signal connection lines (wire connections), but also of their interfaces and contacts, as well as deviations in the functionality of the individual subscribers, particularly their operating parameters, must be recognized quickly, reported to the control center, and eliminated as quickly as possible. These are, in particular, short circuit, wire break, or absence of devices on the device loop.
In the following, a device loop is understood to be a ring bus system in which devices that can be individually addressed (for example in hazard detectors, fire detectors, actuators, etc.) are connected with a hazard alarm control panel by way of a connection line, which ensures not only the supply of power but also the data transmission. The connection line can be configured as a two-wire line, for example, but it can also comprise multiple lines. A hazard alarm control panel (HACP) can be configured, for example, as a fire alarm control panel (FACP), an extinguishing control panel, a combined fire alarm and extinguishing control panel, an intrusion control panel, an emergency control panel, a gas alarm control panel, etc. A hazard alarm system (HAS) is the term for all of the devices/participants, etc., connected with the control panel in question, and the control panel, which is ready for operation. A possible variant of a HAS is a fire alarm system (FAS).
The occurrence of functional problems on device loops is taken into account by means of constant monitoring and regular checks of the alarm devices.
In this connection, however, not only do the peripheral devices connected with a hazard alarm control panel have to be monitored, but also the functionality of the circuit parts of the hazard alarm control panel itself has to be monitored.
In the following, the term “device” is supposed to be understood to mean any type of sensor, detector, hazard detector, fire detector, alarm transmitter, emergency call device, or control and switching device for control or shut-off of devices such as air conditioning or extinguishing systems, which are connected with a hazard alarm control panel, particularly as alarms, by way of a connection line, as line modules.
The communication circuit can be implemented both as a fixed component of the HAS (for example a single-board system) or as a module controlled by the microprocessor system of the HAS, or as an independent module having its own microprocessor system, in a modular HAS.
In this connection, the present invention particularly relates to a communication circuit disposed in a hazard alarm control panel, which circuits are particularly responsible for data exchange and monitoring of the individual subscribers connected with the connection line.
It is known that the data communication between the communication circuit and the devices takes place by way of a ring bus system and a data transfer controller, in most cases, preferably in bit-serial form and in half-duplex mode.
In this connection, the data of the devices that can be individually addressed by way of the ring bus system are modulated up to the supply voltage made available by the hazard alarm control (HACP).
To monitor the data traffic and the supply voltage of the device loop, in other words of the connection line and its devices, the communication circuit usually has different functional units that are switched one behind the other.
These are preferably a functional unit for the voltage supply of the device loop, a voltage pulse generator for modulation of the supply voltage of the HACP, and a voltage measurement unit for checking proper modulation of the supply voltage.
Since the devices respond to the data packets received by modulated voltage pulses by modulating their power consumption, a current measurement unit for detection of the device response (current increase) furthermore follows. Important conclusions concerning the functioning ability of the connection line and of the individual devices can be drawn from the detection of the current increase response by this current measurement unit.
An output unit for connecting the hazard or fire alarm control panel (FACP) to the device loop, in terms of circuit technology, follows as an additional functional unit.
By switching the output unit, it is possible to separate the device loop from the HACP/FACP and to connect it.
The aforementioned functional units of the communication circuit are controlled by an integrated control unit, which is preferably configured as a microprocessor system.
In order to guarantee the functional safety of a hazard alarm system, in other words the hazard alarm control panel with one or more device loops connected with it, various monitoring mechanisms and tests of the participating modules and device in the device loops are required.
However, not only the functionality and operational safety of the connected device loop, but also reliable functioning of the hazard alarm system and its modules themselves are important for safe operation of a hazard alarm system.
Therefore it is necessary, for safety-technology reasons, to regularly check the communication circuit that is responsible for the power supply and the data traffic with the device loops, and to monitor it for proper functioning. Numerous methods and circuit arrangements are known from the literature, particularly for monitoring the functionality of loop devices.
For example, German Patent Application No. DE 10 2008 003 799 A1 describes a monitoring device configured as a module for monitoring the operating state of supply and/or signal lines, which is suitable and configured for integration into an alarm system.
In particular, wire breaks and short circuits that are about to happen are supposed to be detected with this known monitoring device.
Another device for recognizing interruptions on a ring bus that are about to happen is known from German Patent Application No. DE 20 2008 009 211 U1.
In the German Patent DE 966199, a testing device for reception control centers of alarm systems is indicated, with which devices accommodated in the reception control center, such as relays, dialers, display and recording elements, are subjected to testing. For this purpose, the alarm loop is uncoupled from the control center, and a line simulation device equipped with test alarms of the same construction and a line simulation device with defect simulation points, such as the alarm loop, and in the form of an external test kit, is coupled to the control center. However, here, real alarms having the same construction are required to check the telephone relays, and no adjustment possibilities are provided for testing parameters of different alarms.
However, none of these monitoring and testing devices that have been presented are capable of or are designed for testing the control and communication circuits that are responsible for control and signal transmission of the alarm systems, in the hazard alarm or fire alarm control panels, on their own, in an automated, rapid and flexible manner.
This particularly holds true for monitoring devices in which alarm systems of different constructions are used.